// 数组
var my_arr = [1, 2, 3, 4];
// 元祖
var tuple = [1, 'a', 'b'];
console.log(my_arr.join('-')); // 1-2-3-4
my_arr.push(5);
console.log(tuple.join('-')); // 1-a-b
tuple.push('c');
console.log(my_arr);
console.log(tuple);
